OK to unplug MAF sensor and drive car?

[guitarfish]

I have been trying to diagnose a problem on my '02 GP. My mechanic thinks it may be the MAF sensor, but isn't sure. My question: can I unplug the MAF sensor and drive the car, for the purpose of seeing if the symtoms change?

the symptoms: Driving the car under load, it hesitates. Classic feel that you get when spark plugs start going bad. I installed new double platinum plugs, and got a replacement set of GM wires under warranty, and put everything in, it was looking great. Unfortunately, I didn't fix anything.

I can easily reproduce it doing 20mph up a steep hill near my house. It also lunges forward, falls back over and over on hills.

If I unplug the MAF, and it rides smooth, I'm thinking that might be the info I'm looking for.

[00GTP4ME]

I've never done it myself, but I've seen the guys on here suggest doing that several times. Unplug the MAF and if it drives better = bad MAF. I'll let them speak for themselves, but I'm thinking you've got it nailed. Have you tried cleaning the MAF to see if that improves anything?

[tblake]

ran with mine unplugged for a week while I waited for my replacement to ship.

[tblake]

or swap it with the one on your 08 for diagnosis. If the 08 even still has one.

[3100]

GM MAF test procedure: while engine is running tap the top of the MAF sensor with screwdriver handle several times, and if the idle changes for a second or two replace the MAF.

[CrazyHorst]

Nothing bad happens. The downside is the PCM has to "lookup" fuel pulsewidth values from a table based on ERPM and TPS (kinda reverting to TBI technology except with more injectors and sequential fire). I think while it doesn't hurt durability or power it does not run as efficiently.

The idle also seems to be higher with MAF disconnected in order to keep it stable.

[buckeyeguy]

I may be wrong, but doesn't that put a lot of strain on the EGR if you keep running it like that?

[CrazyHorst]

Um, strain on the EGR?

Keep in mind that EGR is used for two purposes...reduce flame temps to combat NOx formation and it also is a fuel economy "tool" as it basically displaces air/fuel mixture. The tradeoff is it is a "diluent" to the swirling mixture and obviously reduces power.

In any case, my thoughts are if the engine can't closely regulate air/fuel (ala the MAF sensor disconnected - hence running in "backup mode") the strategy would be to *lessen* the use of EGR. Basically an over-excursion into EGR is recipe for stumbling, misfires, and worst-case flame-out (stall).

Also I'm not aware of any "strain". Its just a solenoid valve commanded to be open or not.